Apparatus for making hollow rubber articles



NW, 13 N45; N. E. TELLOTSQN APPARATUS FOR MAKING HOLLOW RUBBER ARTICLES Filed Mai-ch 3, 1941 Patented Nov. 13, 1945 UNITED STATES PATENT OFFICE APBARATUSEOR MAKING HOLLOW RUBBER ARTICLES.

N'eikE. Tillotson, Wat'ertown, Mass.

ApplicationMarch 3, 1941, ScriaLNo..381-,490

' r Claim. (01. I8'-41'-) The present invention relates to apparatus for making hollow rubber articles, particularly concerned with the manufacture: of hQ110W 3J1- ticles of complex shape, suchas' dolls. and toys in human and animal form.

The production of dipped hollow rubber articles of simple shape may be carried; out: by theuse, of solid-i forms. Forarticles of complex shape, the forms may be made of paper; or cardboard; which is: necessarily destroyed in removing it from the finished article; this procedure is used mainly for producing flat articles, such as balloons, which are later to be inflated. Neither of these methods is applicable to the manufacture of what may be described as three-dimensional articles of complex shape; namely, articles which assume their proper shape in the forming operation.

The principal object of the present invention is to provide an inexpensive apparatus for making three-dimensional hollow articles. To this end, the invention contemplates as its principal feature the use of a flexible and collapsible form preferably made of rubber, which may be clipped in the rubber solution or suspension and from which the clipped article may be conveniently stripped without damage either to the article or the form. The apparatus is particularly suitable for the manufacture of articles having protruding portions, of which four-legged toy animals will serve as an example.

Other features of the invention will appear from the following description of the preferred form of the invention.

In the accompanying drawing, illustrating the manufacture of a toy cow according to the present invention, Fig. 1 is an elevation of the dipping form for the head portion of the cow; Fig. 2 is an elevation of the dipping form for the body portion of the cow; Fig. 3 is a perspective view of the dipping tank; Fig. 4 is a section of the mold and .coating through the body portion on line 4-4 of Fig. 2; Fig. 5 is an elevation of the completed toy; and Fig. 6 is a sectional detail view illustrating the preferred method of joining the sections.

The invention is herein illustrated and described as embodied in a process for the manufacture of a toy animal represented by the cow of Fig. 5. The toy is a three-dimensional structure and is able to stand without being inflated. It will be observed that the structure of the toy is complex, in that it has four long hollow legs, a representation of a collar and bell, and hollow extended ears, all of which would present a diflicult, not, impossible, stripping problem with solidtfnrms.

The toy animal. is. madetWQi parts, which are joined a. manner to: be.- hereinafter described. For" this, purpose there are provided two.

molds: or; dipping forms, one for the head portion,,; as shown: inFigrl, and one for the bodyportion, as:- shown; in Fig. 2. The formshown in Fig. I of: rubber, preferably hollow, and of a contour; tovdefinethe head ,8 of the-animal, the bell l0 and the collar 12. The form is provided with an extended tubular neck l4. Inserted tightly into the neck is a plug l6, through which passes a metal tube [8, threaded at opposite ends to receive the nuts 20 and 22. The neck is tightly secured about the plug by a binding wire 24. The whole structure. is mounted on a clipping rack 26, to which it is secured by the nut 22.

The body form shown in Fig. 2 is similar to the form heretofore described, except for its shape. It comprises a hollow body 28 to which are connected long protruding legs 30. The legs, because of their flexibility, need not be hollow in this instance, but if they are shorter and thicker, as in a mold for a toy elephant, for example, it is preferable to make them hollow. The neck portion 32 is similar to the neck [4, but slightly larger in diameter, to facilitate joining the two parts of the completed toy.

The molds are made of rubber, and may be manufactured by casting internally in plaster molds, or according to any other suitable procedure.

The molds, after being mounted on the rack 26, are dipped in a liquid rubber bath 34, preferably a latex suspension. Before dipping, the forms may'be coated with suitable material to prevent adherence of the coating to the rubber form. The forms are immersed in the bath, so that the neck portions l4 and 32 are partly submerged therein. After immersion of sufficient time to insure proper coating, the forms are withdrawn and the coating is allowed to harden or cure. The coatingis of suflicient thickness to maintain the shape of the article, as distinguished from thin coatings used for inflatable toys.

Fig. 4 is a sectional view, illustrating the latex coating 36 surrounding the rubber form. This section is taken approximately on the line 4-4 of Fig; 2, and illustrates the three-dimensional shape of the article.

After the coatings or envelopes have sufficiently hardened or cured, they are stripped from the forms. The coating may be freed from the form byinserting a hollow needle or nozzle between the form and the coating and applying air pressure, which will act to distend the coating slightly and also to collapse the internal form. The tube l8 'afiords communication between the interior of the form and the atmosphere, so that bending and collapsing of the form are not resisted by internal air pressure. The coating is pulled away from the form and worked back over the rear portion thereof. Inperforming this operation, the protru n po ti nsfs h as the g i telh nt b lq i ward, thus allowing the coating to be stripped off without undue stretching. The exact procedure used in stripping will vary withtheshape of the article and need not be described in detail, since],

the manipulative steps will be readily understood by those skilled in the art of handlingrubber, prode ucts.

The bending or flexing of the protruding I 7 portions of the form permits easy removal of the coating from the form without excessive stretching and without danger of tearing the material.

After stripping, the portions 38 and 40 of the coating which are formed over the neck portions l4 and 32 are trimmed to appropriate lengths and these portions are used to join the two sections together, as indicated; in Fig. '6: The tubular neck 40 formed at the front of the body portion-is turned inward and the tubular neck 38 formed at the two being cemented together. As previously described, the neck 38 is smaller than the neck 40 30 the rear of the head portion is inserted therein,

in order to obtain a smooth fit. The provision of a collar I2, as in the illustrated embodiment of the invention, is desirable, though not necessary, in order to conceal the joint.

The invention primarily contemplates the use of three-dimensional forms which are flexible and capable of being compressed, collapsed and otherwise distorted to facilitate the removal of the formed articles, its preferredembodiment, the inventionmakesjuse of forms which are hollow, or mainly so, and are therefore most readily subjected to the stripping operations, but it will be understood that forms may be employed which are not hollow, e. g., of soft rubber, which are sufficiently flexible and are capable of being distorted to allow removal of the formed articles. 

